Dont talk crap about fences. Boots on the ground!
How about arming and letting those already there do likewise? Their hands are tied currently. Along with building a stable barrier where that is possible...it's not one or the other..it's both
No worries. Walls do help, not going to deny that - but only if you have them constantly patrolled with sufficient troops with very specific ROE. Both Israel and Berlin have/had that.